JPH0319273A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the degree of freedom of design by electrically connecting a resistor and a wiring layer via a silicide part, and arranging the silicide part in the region except the contact part between the wiring layer and the resistor. CONSTITUTION:Polysilicon resistors 1, 2 are formed between aluminum wirings 1, 2, and silicide 7 is formed in the nearly central parts of the resistors 1, 2. The resistors 1, 2 have mutually different values, and electrically connected with the wirings 3, 4 via silicide 6 formed in contact holes. The silicide 7 is formed in the polycrystalline silicon region except holes 5; as to the resistor 2, the silicide 6 is formed only in the hole 5 parts. In this manner, the resistors 1, 2 have the silicide 7 also in the part except the contact part with the wirings 3, 4, and the length and the width of the silicide part 7 are changed in the case of design change. Hence an aperture part forming mask only may be changed, so that design becomes free.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to the structure of a polycrystalline silicon resistor. [Prior Art] Conventionally, this type of polycrystalline silicon resistor (hereinafter abbreviated as polycrystalline resistor) consists of forming a polycrystalline silicon layer so as to have a predetermined size and resistance value, and connecting metal wiring to both ends of the polycrystalline silicon layer.
For example, it was completed by connecting aluminum wiring (hereinafter abbreviated as aluminum wiring). Details of the prior art will be explained with reference to FIGS. 5 and 6. The resistive resistor 11 is provided between the aluminum wirings 3 and 4, and silicide 6 is formed at the contact portion with the aluminum wirings 3 and 4. (The silicide 6 is shaded for convenience, but its cross section is not shown.) Next, a conventional method for manufacturing a polysilicon resistor will be described.

Polycrystalline silicon is deposited on the insulating film 8 to a thickness of 0.2 to 0.3 μm, and impurity ions are implanted into the polycrystalline silicon to obtain a predetermined resistance value. Next, polysilicon resistor 11 is formed by etching the polycrystalline silicon using photolithography using the resist as a mask. An insulating film 9 having a thickness of 0.3 to 0.5 μm is formed thereon, and openings are formed on predetermined contact portions of the polysilicon resistor 1l using photolithography. When a high-melting point metal such as platinum which easily forms silicide is deposited thereon and heat treatment is applied at about 400 to 500°C, silicide 6 is formed in the exposed portion of polysilicon resistor 11. After that, after etching the platinum that was not silicided by wet etching with aqua regia, 1.
An insulating film 10 having a thickness of 0 to 1.5 μm is formed, and a contact hole 5 for connection to an aluminum wiring is formed by photolithography. On top of that, a high melting point metal such as tungsten or titanium is applied as a barrier metal to a thickness of 1. Aluminum with a thickness of 0 to 1.5 μm is deposited, and the aluminum is patterned into a predetermined wiring shape using photolithography technology to form aluminum wirings 3 and 4. As mentioned above, polysilicon resistors in conventional semiconductor devices have a structure in which silicide is present only in the contact area. [Problems to be Solved by the Invention] The conventional polysilicon resistor described above forms silicide only in the contact area with the aluminum wiring, but if resistors with multiple different resistance values are required, each resistor has a large It is necessary to change the impurity ion implantation amount or to change the impurity ion implantation amount, which has the disadvantage that the process time becomes longer due to an increase in design man-hours or ion implantation steps.

Also, if you want to change the resistance value due to design changes, etc., if you change the resistance size, the polysilicon resistance 1
The shape of 1, the position of silicide 6, the position of contact hole 5, and the pattern of aluminum wiring 3 and 4 were changed.
As a result, four types of masks must be used in each process: a resistance type mask, a silicide type mask, a contact type mask, and a mask for aluminum wiring formation. Therefore, there is a drawback that the time and cost required for changes are large.

An object of the present invention is to provide a semiconductor device in which the degree of freedom in design is improved in response to changes in resistance values without significantly increasing the number of man-hours in the manufacturing process.

[Means to solve the problem]

A semiconductor device of the present invention includes a resistor formed of a layer of polycrystalline silicon, first and second silicide parts formed at both ends of the resistor, and the first and second silicide parts. a wiring layer electrically connected to the resistor via a third silicide portion provided in a predetermined region of the polycrystalline silicon layer other than a contact portion between the wiring layer and the resistor. ing.

With this structure, any desired silicide region can be formed into a polycrystalline silicon layer by simply changing the shape of the silicide region or the mask used, making it possible to achieve low resistance without increasing the number of steps. Become.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 shows a plan view of a first embodiment of the present invention.

Voltage resistors 1 and 2 are formed between aluminum wirings 3 and 40. The polysilicon resistor AI has a silicide 7 formed approximately in the center, and the polysilicon resistor A1 and the resistor B2 have different resistance values. These polysilicon resistors 1 and 2 are connected to aluminum wiring 3 as in the prior art.
and 4 are electrically connected to each other via silicide 6 provided in contact hole 5. (Silicide 6
, 7 are shaded for convenience, but do not represent cross sections. ) Polysilicon resistor A1 and polysilicon resistor B2 will be described in detail below with reference to FIGS. 2(a) and (b).

As shown in FIG. 2(a), the polysilicon resistor Al is provided with silicide 6 at the contact portions with the aluminum wirings 3 and 4, that is, at the contact holes.

Further, silicide 7 is formed in the polycrystalline silicon region other than the contact hole 5. In addition, the resistor B2
In this case, silicide 6 is formed only in the contact hole 5 portion.

Next, a manufacturing method of an embodiment of the present invention will be described. Polycrystalline silicon is deposited on the insulating film 8 to a thickness of 0.2 to 0.3 μm, and impurity ions are implanted into the polycrystalline silicon. Polycrystalline silicon is etched by photolithography using a resist as a mask to form polysilicon resistors A1 and B2. An insulating film 9 having a thickness of 0.3 to 0.5 μm is formed thereon, and holes are formed in the portions to be silicided by photolithography. In this embodiment, the polysilicon resistor A1 has an opening in the contact hole and, for example, in the center of the resistor, and the polysilicon resistor B2 has an opening only in the contact hole. When a metal such as platinum is deposited thereon and heat treated at 400 to 500° C., silicides 6 and 7 are formed in the polycrystalline silicon in the openings of the insulating film 9. After etching the unsilicided platinum, an insulating film 10 with a thickness of 1.0 to 1.5 μm is formed, and a contact hole 5 for connecting the resistor and wiring is formed by photolithography. On top of that, barrier metal and aluminum with a thickness of 1.0 to 1.5 μm are deposited.
Aluminum wirings 3 and 4 are formed by patterning aluminum using photolithography technology. Like this,
The resistor A1 has a silicide structure in the 5 contact holes for wiring connection and the center of the resistor, and the resistor B
No. 2 has a silicide structure only in 5 portions of the contact hole for wiring connection.

Next, the function of the polysilicon resistor of this embodiment will be explained.

Contact hole 5 of polysilicon resistor A1 and resistor B2
The silicide structure of the part reduces the resistance and interconnection resistance. The polysilicon resistor A1 also has a silicide structure in the center, which functions to short-circuit both ends of the silicide.

Therefore, the resistance value of the polysilicon resistor A1 is lower than that of the polysilicon resistor B2 which does not have a silicide structure in the center. In this way, by forming a silicide structure in the center of the resistor, the resistance value can be changed.

In the present invention, a case where a design change in resistance value occurs will be explained with reference to FIGS. 3 and 4. In FIG. 4, the resistance value of the polysilicon resistor 11 is Ru. Next, if a resistance value smaller than the resistance value Rl1 is required due to a design change, the contact hole 5 of the polysilicon resistor l1
In addition to the silicide portions, silicide portions 12 may be formed at two locations, for example, as shown in FIG. Mask changes in such design changes can be accomplished by simply changing the mask for a certain region of silicide type, and can be achieved by changing only one process.

〔Effect of the invention〕

As explained above, the present invention has a silicide structure in parts other than the contact part with the wiring of the polysilicon resistor, and the resistance value can be changed simply by changing the length, width, etc. of this silicide part. This makes the design easier. Furthermore, if you want to change the resistance value of the polycrystalline silicon layer due to design changes, etc., the length of the silicide part formed other than the contact part,
In order to change the width etc., it is only necessary to change the shape of the opening or the mask, which has the advantage of greatly reducing the number of man-hours.

FIG. 6 is a plan view showing the resistance at the time of design change in the conventional example.

l... Polysilicon resistance A, 2... Polysilicon resistance B, 3, 4... Aluminum wiring, 5...
...Contact hole, 6,7.12...Silicide, 8,9.10...Insulating film, l1...
・Polysiliary resistance.

Claims (1)

[Claims] a resistor formed of polycrystalline silicon; first and second silicide portions provided at both ends of the resistor;
A wiring layer electrically connected to the resistor through the first and second silicide portions, and a predetermined region of the polycrystalline silicon layer other than a contact portion between the wiring layer and the resistor. A semiconductor device characterized in that it has a third silicide portion.